The present invention disclosed herein relates to an apparatus and system for measuring a water level by using magnetostriction displacement.
The hydrologic cycle is called the continuous movement of water on, above, and below the surface of the earth. The water on the surface of the earth, i.e., surface water, exists in a stream, lake, wetland, gulf, and ocean. Also, the surface water may exist in snow and glacier states. Water existing under the surface of the earth is called groundwater. Here, soil water is included in the groundwater. However, although water movements in air and on the surface of the earth are easily patterned, it is very difficult to pattern movement of the groundwater. The groundwater flows from a recharge area to a discharge area along different paths. Generally, a flow of the groundwater starts from a groundwater table to flow along a groundwater system and is finished at a pumping well. Rainfall infiltrates into the ground through an unsaturated zone to recharge the groundwater. A flow path of an unconfined aquifer that is the uppermost portion of an aquifer has a length of several tens to several hundreds fts. The water introduced into the unconfined aquifer flows for several days to several years.
In one environment, a gaining stream and losing stream are continuous. That is, one stream may always receive the groundwater from the groundwater system, and the other stream may always supply the water into the groundwater system. In the other environment, the losing stream and the gaining stream may change along the stream according to areas. Furthermore, the gaining stream and the losing stream may be alternately generated according to transpiration of the groundwater due to focused recharge, temporary flood, and plants around the stream. In other words, the groundwater system may complicatedly interact with the surface water system all the time.
There is a phenomenon that is called bank storage as interaction between the groundwater and the surface water in almost all streams. The bank storage is a phenomenon in which a water level of the stream rapidly increases to get higher than that of the groundwater therearound, thereby allowing the stream water to flow to and be stored in a riverbank. The bank storage may occur when it rains suddenly, when snow melts very fast, or when water is suddenly introduced from an upstream reservoir. In this case, if a water level of the stream does not continuously increases, the water stored in the riverbank returns within several days to several weeks. If the water level of the stream floods over the riverbank, wide groundwater recharge may be generated over the whole areas. Like this, when the groundwater recharge is generated due to the flood, it takes several weeks, months, or years until the water returns to the stream.
Therefore, it is necessary to develop a sensor for accurately measuring the water level of the surface water and the groundwater and a system for monitoring the interrelation therebetween.
The inventor has completed the present invention based on the findings so as to solve the above-described limitations.